/**
     * Copyright (c) 2016 hustcc
     * License: MIT
     * Version: %%GULP_INJECT_VERSION%%
     * GitHub: https://github.com/hustcc/canvas-nest.js
    **/
   ! function() {
    //��װ������ѹ��֮������ļ���С
    function get_attribute(node, attr, default_value) {
      return node.getAttribute(attr) || default_value;
    }
    //��װ������ѹ��֮������ļ���С
    function get_by_tagname(name) {
      return document.getElementsByTagName(name);
    }
    //��ȡ���ò���
    function get_config_option() {
      var scripts = get_by_tagname("script"),
        script_len = scripts.length,
        script = scripts[script_len - 1]; //��ǰ���ص�script
      return {
        l: script_len, //���ȣ���������id��
        z: get_attribute(script, "zIndex", -1), //z-index
        o: get_attribute(script, "opacity", 0.6), //opacity
        c: get_attribute(script, "color", "0,0,255"), //color
        n: get_attribute(script, "count", 99) //count
      };
    }
    //����canvas�ĸ߿�
    function set_canvas_size() {
      canvas_width = the_canvas.width = window.innerWidth || document.documentElement.clientWidth || document.body.clientWidth,
      canvas_height = the_canvas.height = window.innerHeight || document.documentElement.clientHeight || document.body.clientHeight;
    }
  
    //���ƹ���
    function draw_canvas() {
      context.clearRect(0, 0, canvas_width, canvas_height);
      //����������͵�ǰλ����������
      var e, i, d, x_dist, y_dist, dist; //��ʱ�ڵ�
      //��������ÿһ����
      random_points.forEach(function(r, idx) {
        r.x += r.xa,
        r.y += r.ya, //�ƶ�
        r.xa *= r.x > canvas_width || r.x < 0 ? -1 : 1,
        r.ya *= r.y > canvas_height || r.y < 0 ? -1 : 1, //�����߽磬���򷴵�
        context.fillRect(r.x - 0.5, r.y - 0.5, 1, 1); //����һ������Ϊ1�ĵ�
        //����һ���㿪ʼ
        for (i = idx + 1; i < all_array.length; i++) {
          e = all_array[i];
          // ��ǰ�����
          if (null !== e.x && null !== e.y) {
            x_dist = r.x - e.x; //x����� l
            y_dist = r.y - e.y; //y����� n
            dist = x_dist * x_dist + y_dist * y_dist; //�ܾ���, m
  
            dist < e.max && (e === current_point && dist >= e.max / 2 && (r.x -= 0.03 * x_dist, r.y -= 0.03 * y_dist), //������ʱ�����
              d = (e.max - dist) / e.max,
              context.beginPath(),
              context.lineWidth = d / 2,
              context.strokeStyle = "rgba(" + config.c + "," + (d + 0.2) + ")",
              context.moveTo(r.x, r.y),
              context.lineTo(e.x, e.y),
              context.stroke());
          }
        }
      }), frame_func(draw_canvas);
    }
    //���������������ӵ�body��
    var the_canvas = document.createElement("canvas"), //����
      config = get_config_option(), //����
      canvas_id = "c_n" + config.l, //canvas id
      context = the_canvas.getContext("2d"), canvas_width, canvas_height,
      frame_func = window.requestAnimationFrame || window.webkitRequestAnimationFrame || window.mozRequestAnimationFrame || window.oRequestAnimationFrame || window.msRequestAnimationFrame || function(func) {
        window.setTimeout(func, 1000 / 45);
      }, random = Math.random,
      current_point = {
        x: null, //��ǰ���x
        y: null, //��ǰ���y
        max: 20000 // Ȧ�뾶��ƽ��
      },
      all_array;
    the_canvas.id = canvas_id;
    the_canvas.style.cssText = "position:fixed;top:0;left:0;z-index:" + config.z + ";opacity:" + config.o;
    get_by_tagname("body")[0].appendChild(the_canvas);
  
    //��ʼ��������С
    set_canvas_size();
    window.onresize = set_canvas_size;
    //��ʱ���λ�ô洢���뿪��ʱ���ͷŵ�ǰλ����Ϣ
    window.onmousemove = function(e) {
      e = e || window.event;
      current_point.x = e.clientX;
      current_point.y = e.clientY;
    }, window.onmouseout = function() {
      current_point.x = null;
      current_point.y = null;
    };
    //�������config.n����λ����Ϣ
    for (var random_points = [], i = 0; config.n > i; i++) {
      var x = random() * canvas_width, //���λ��
        y = random() * canvas_height,
        xa = 2 * random() - 1, //����˶�����
        ya = 2 * random() - 1;
      // �����
      random_points.push({
        x: x,
        y: y,
        xa: xa,
        ya: ya,
        max: 6000 //մ������
      });
    }
    all_array = random_points.concat([current_point]);
    //0.1������
    setTimeout(function() {
      draw_canvas();
    }, 100);
  }();